16. select from saved channel
save selection to a path
stroke path by px with black on a new transparent layer

change the Mode to 'Grain Merge' and reduce the Opacity to 15%

17. create new transparent layer on top of text layer
fill selection with pattern (i used the 'Leather' pattern that comes with Gimp)
add white layermask

18. stroke on the layermask a gradient from black to white, to make the pattern partly translucent.

Put the pattern-filled layer under the stroke layer.

This is your glossy acrylic texteffect based on xgeous' technique and here is a screenshot of all the layers:

Now i will show you the Esper technique of how to modify the gloss.

19. apply an alpha-curve to the highlight like this:

20. then duplicate this layer twice and move your three linked gloss layers 1px down and 1 px to the right
your result will look like this:

For yet another variation we will delete the pattern-filled layer and duplicate the Grid-filled layer.
On Grid-filled layer one, we apply a layermask 'Channel' and 'Invert Mask'.
This will make the grid inside the text invisible.

On the second Grid-filled layer on top of the first, we will apply a layermask 'Channel', so everything outside the text is invisible.

Next we duplicate our saved channel and blur it by 20px.
Activate the upper Grid-filled layer (with the grid inside the text) and apply 'Displace' on it, with the blurred 20 channel as the map.
I used a value of 100px.